All the wisdom of the ages, all the stories that have delighted mankind for centuries, are easily and cheaply available to all of us within the covers of books — but we must know how to avail ourselves of this treasure and how to get the most from it. The most unfortunate people in the world are those who have never discovered how satisfying it is to read good books. I am most interested in people, in meeting them and finding out about them. Some of the most remarkable people I’’ve met existed only in a writer’’s imagination, then on the pages of his book, and then, again, in my imagination. I’’ve found in books new friends, new societies, new worlds. If I am interested in people, others are interested not so much in who as in how. Who in the book includes everybody from science-fiction superman two hundred centuries in the future all the way back to the first figures in history; How covers everything from the ingenious explanations of Sherlock Holmes to the discoveries of science and ways of teaching manners to children. Reading is a pleasure of the mind, which means that it is a little like a sport: your eagerness and knowledge and quickness make you a good reader. Reading is fun, not because the writer is telling you something, but because it makes your mind work. Your own imagination works along with the author’’s or even goes beyond his. Your experience, compared with his, brings you to the same or different conclusions, and your ideas develop as you understand his. Every book stands by itself, like a one-family house, but books in a library are like houses in a city. Although they are separate, together they all add up to something; they are connected with each other and with other cities. The same ideas, or related ones, turn up in different places; the human problems that repeat themselves in life repeat themselves in literature, but with different solutions according to different writings at different times. Books influence each other; they link the past, the present and the future and have their own generations, like families. Wherever you start reading you connect yourself with one of the families of ideas, and, in the long run, you not only find out about the world and the people in it, you find out about yourself, too. Reading can only be fun if you expect it to be. If you concentrate on books somebody tells you, you "ought" to read, you probably won’’t have fun. But if you put down a book you don’’t like and try another till you find one that means something to you, and then relax with it, you will almost certainly have a good time — and if you become, as a result of reading, better, wiser, kinder, or more gentle, you won’’t have suffered during the process. The sentence "Although they are separate, together they all add up to something;" means ________.
A. that although they are separate, when they are put together they mean something
B. that although they are separate, they can help you add something
C. that although they are separate, they are connected with each other
D. that although they are separate, they influence each other